Field of Invention
The present invention relates to displays, and particularly to a method for manufacturing a TFT array substrate.
Description of Prior Art
Thin film transistor-liquid crystal displays (TFT-LCDs) are the most widely used flat panel displays. With methods for manufacturing liquid crystal displays becoming more and more mature and advanced, manufacturing process is simplified, manufacturing time is reduced, and an important way for competing in the industry is to increase process efficiency to reduce production costs.
Indium gallium zinc oxide (IGZO) is amorphous oxide including indium, gallium, and zinc. The IGZO has a high mobility rate, and a mobility rate of current carrier is 20-30 times more than amorphous silicon to improve charge-discharge speed between the TFT and pixel electrode, and has a high on current and a low off current to rapidly turn on and off, to improve pixel response speed, to have faster refresh rates, and improve a line scanning rate of pixels to make TFT-LCDs have an ultrahigh resolution.
Referring to FIG. 1, in a conventional IGZO 4 MASK process, because a halftone photomask 101 has a source and drain electrode metal layer 205 and the IGZO 204 exposed at the same time, then is etched 2 or 3 times by acid, a channel 206 is formed. Because of multiple acid etchings, the source and drain electrode metal layer 205 and the IGZO 204 become over etched.